Publications by authors named "Seiji Kojima"

461 Publications

A patient with very early onset FH-deficient renal cell carcinoma diagnosed at age seven.

Fam Cancer 2021 Jun 22. Epub 2021 Jun 22.

Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is caused by heterozygous germline variants in the fumarate hydratase (FH) gene and is associated with increased susceptibility to cutaneous leiomyomas, uterine leiomyomas, and renal cell carcinoma (RCC). HLRCC-associated RCC usually occurs in the middle age, with the median age being 40-44 years. This report describes a seven-year-old (84-month-old) male who developed a large right kidney tumor with multiple cystic lesions that contained enhanced solid components. There was no evidence of distant metastasis. The male patient underwent right nephrectomy and has been recovering well without metastasis or recurrence. Pathological examination revealed that tumor cells with relatively prominent nucleoli and surrounded by halos, were located in a limited area. Immunohistochemical staining was negative for FH. Whole-exome sequencing identified his germline variant in the FH gene and its loss of heterozygosity in the tumor. At nine years (114 months) of age, the male patient showed no recurrence of the tumor. This was the youngest-onset case of HLRCC-associated RCC to date. This report may affect the starting age for future RCC-surveillance programs for patients with HLRCC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10689-021-00268-8DOI Listing
June 2021

A slight bending of an α-helix in FliM creates a counterclockwise-locked structure of the flagellar motor in Vibrio.

J Biochem 2021 Jun 18. Epub 2021 Jun 18.

Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan.

Many bacteria swim by rotating flagella. The chemotaxis system controls the direction of flagellar rotation. Vibrio alginolyticus, which has a single polar flagellum, swims smoothly by rotating the flagellar motor counterclockwise (CCW) in response to attractants. In response to repellents, the motor frequently switches its rotational direction between CCW and clockwise (CW). We isolated a mutant strain that swims with a CW-locked rotation of the flagellum, which pulls rather than pushes the cell. This CW phenotype arises from a R49P substitution in FliM, which is the component in the C-ring of the motor that binds the chemotaxis signaling protein, phosphorylated CheY. However, this phenotype is independent of CheY, indicating that the mutation produces a CW conformation of the C-ring in the absence of CheY. The crystal structure of FliM with the R49P substitution showed a conformational change in the N-terminal α-helix of the middle domain of FliM (FliMM). This helix should mediates FliM-FliM interaction. The structural models of wild-type and mutant C-ring showed that the relatively small conformational change in FliMM induces a drastic rearrangement of the conformation of the FliMM domain that generates a CW conformation of the C-ring.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jb/mvab074DOI Listing
June 2021

Integrated diagnosis based on transcriptome analysis in suspected pediatric sarcomas.

NPJ Genom Med 2021 Jun 15;6(1):49. Epub 2021 Jun 15.

Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.

Pediatric solid tumors are a heterogeneous group of neoplasms with over 100 subtypes. Clinical and histopathological diagnosis remains challenging due to the overlapping morphological and immunohistochemical findings and the presence of atypical cases. To evaluate the potential utility of including RNA-sequencing (RNA-seq) in the diagnostic process, we performed RNA-seq in 47 patients with suspected pediatric sarcomas. Histopathologists specialized in pediatric cancer re-evaluated pathological specimens to reach a consensus diagnosis; 42 patients were diagnosed with known subtypes of solid tumors whereas 5 patients were diagnosed with undifferentiated sarcoma. RNA-seq analysis confirmed and refined consensus diagnoses and further identified diagnostic genetic variants in four of the five patients with undifferentiated sarcoma. Genetic lesions were detected in 23 patients, including the novel SMARCA4-THOP1 fusion gene and 22 conventional or recently reported genetic events. Unsupervised clustering analysis of the RNA-seq data identified a distinct cluster defined by the overexpression of rhabdomyosarcoma-associated genes including MYOG and CHRNG. These findings suggest that RNA-seq-based genetic analysis may aid in the diagnosis of suspected pediatric sarcomas, which would be useful for the development of stratified treatment strategies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41525-021-00210-yDOI Listing
June 2021

Putative spanner function of the PomB plug region in the stator rotation model for flagellar motor.

J Bacteriol 2021 Jun 7:JB0015921. Epub 2021 Jun 7.

Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.

Bacterial flagella are the best-known rotational organelles in the biological world. The spiral-shaped flagellar filaments that extending from the cell surface rotate like a screw to create a propulsive force. At the base of the flagellar filament lies a protein motor that consists of a stator and a rotor embedded in the membrane. The stator is composed of two types of membrane subunits, PomA(MotA) and PomB(MotB), which are energy converters that assemble around the rotor to couple rotation with the ion flow. Recently, stator structures, where two MotB molecules are inserted into the center of a ring made of five MotA molecules, were reported. This structure inspired a model in which the MotA ring rotates around the MotB dimer in response to ion influx. Here, we focus on the PomB plug region, which is involved in flagellar motor activation. We investigated the plug region using site-directed photo-crosslinking and disulfide crosslinking experiments. Our results demonstrated that the plug interacts with the extracellular short loop region of PomA, which is located between transmembrane helices 3 and 4. Although the motor stopped rotating after crosslinking, its function recovered after treatment with a reducing reagent that disrupted the disulfide bond. Our results support the hypothesis, which has been inferred from the stator structure, that the plug region terminates the ion influx by blocking the rotation of the rotor as a spanner. The biological flagellar motor resembles a mechanical motor. It is composed of a stator and a rotor. The force is transmitted to the rotor by the gear-like stator movements. It has been proposed that the pentamer of MotA subunits revolves around the axis of the B subunit dimer in response to ion flow. The plug region of the B subunit regulates the ion flow. Here, we demonstrated that the ion flow was terminated by crosslinking the plug region of PomB with PomA. These findings support the rotation hypothesis and explain the role of the plug region in blocking the rotation of the stator unit.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JB.00159-21DOI Listing
June 2021

Echocardiography Monitoring of Pulmonary Hypertension after Pediatric Hematopoietic Stem Cell Transplantation: Pediatric PAH and PVOD after HSCT.

Transplant Cell Ther 2021 May 28. Epub 2021 May 28.

Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550 Japan. Electronic address:

Background: Pulmonary hypertension (PH) is associated with a high morbidity in children receiving hematopoietic stem cell transplantation (HSCT). However, due to the lack of sequential echocardiography, the nature of the condition is not fully understood.

Objectives: To study whether routine echocardiography performed after HSCT could detect patients with PH at an earlier stage and elucidate the role of intervention using tadalafil.

Study Design: This study included 93 consecutive children aged under 18 years, and 109 HSCTs were performed. All underwent routine transthoracic echocardiography during HSCT.

Results: Four children (4%) with median age of 4 years (range, 0.7-6) were found to have PH, and the median tricuspid regurgitation peak velocity (TRV) was 4.1 m/s (range, 3.5-4.2). PH was diagnosed at a median of 52 days (range, 21-118) after HSCT. Among them, three were diagnosed with neuroblastoma and one with infantile leukemia. One developed PH after autologous HSCT, and three received killer immunoglobulin-like receptor ligand-mismatched cord blood. Busulfan was used for conditioning in all patients, and the proportion of patients receiving this medication was significantly higher in the PH group than in the non-PH group (100% vs. 30%, P = 0.011). Three of four patients had a durable response (TRV of ≤2.8 m/s) at a median of 46 (range: 14-79) days after starting treatment with tadalafil. None of them experienced exacerbation of PH, and the treatment was completed at median 96 days (range, 46-212).

Conclusion: Routine echocardiography monitoring after HSCT should be considered in children receiving busulfan, although precise follow-up timings need to be studied further. In addition, safe and effective administration of tadalafil must be ensured by close monitoring.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jtct.2021.05.017DOI Listing
May 2021

Relationship between plasma rabbit anti-thymocyte globulin concentration and immunosuppressive therapy response in patients with severe aplastic anemia.

Eur J Haematol 2021 May 4. Epub 2021 May 4.

Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.

Objectives: Patients with acquired aplastic anemia (AA) without HLA-matched sibling donors or aged >40 years receive immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG). We investigated the relationship between plasma rabbit ATG (r-ATG) concentration and IST response.

Methods: From May 2012 to October 2017, 81 patients with severe AA who required initial IST were included. A 1:1 block randomization was employed for 2.5 and 3.5 mg/kg doses of r-ATG.

Results: No significant difference in response rates was observed between the 2.5 and 3.5 mg/kg groups (63% vs. 58%, P = .894). Median r-ATG concentrations on days 14 and 28 after IST were 15.2 (0.0-97.7) and 1.8 (0.0-74.9 µg/mL), respectively. According to r-ATG concentration, response rates were significantly higher in the group with higher r-ATG concentration than in those with lower r-ATG concentration (day 14, 88% vs. 52%; P = .006 and day 28, 79% vs. 46%; P = .005). In multivariate analysis, higher r-ATG concentrations at day 28 were independent predictors of favorable response to IST at 6 months (odds ratio, 0.29; 95% confidence interval, 0.09-0.93; P = .037).

Conclusions: The present data indicate that higher r-ATG concentration at day 28 resulted in improved IST response.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ejh.13644DOI Listing
May 2021

Hippocampal Atrophy in Pediatric Transplant Recipients with Human Herpesvirus 6B.

Microorganisms 2021 Apr 8;9(4). Epub 2021 Apr 8.

Department of Pediatrics, Fujita Health University School of Medicine, Toyoake 470-1192, Japan.

The aim of this study was to determine whether human herpesvirus 6B (HHV-6B) infection can impair the hippocampus in pediatric hematopoietic stem cell transplant (HSCT) recipients. Study subjects were pediatric HSCT recipients monitored for HHV-6B infection who underwent brain MRI before and after transplantation. Volumetric analysis of the hippocampus was performed. Of the 107 patients that received HSCT at Nagoya University Hospital Between July 2008 and April 2014, 20 were eligible for volumetric analysis. Eight patients had HHV-6B infection, of whom two had encephalopathy at the time of HHV-6B infection. None of the 12 patients without HHV-6B infection had encephalopathy. The median ratio of the right hippocampal volume from before to after transplantation was 0.93 in patients with HHV-6B infection and 1.02 in without HHV-6B infection ( = 0.007). The median ratio of the left hippocampal volume ratio in patients with and without HHV-6B infection was 0.92 and 1.00, respectively ( = 0.003). Among the eight patients with HHV-6B infection, four had a marked reduction in hippocampal volume (volume ratio < 0.90). Only one of these patients had neurological symptoms at the time of HHV-6B infection. The reduction in the hippocampal volume ratio was higher in pediatric HSCT recipients with HHV-6B infection than those without viral infection. Neurological follow-up may be required for pediatric HSCT recipients with HHV-6B infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/microorganisms9040776DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8068176PMC
April 2021

Successful treatment of a novel type I interferonopathy due to a de novo PSMB9 gene mutation with a Janus kinase inhibitor.

J Allergy Clin Immunol 2021 Mar 13. Epub 2021 Mar 13.

Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address:

Background: Type I interferonopathies are a recently established subgroup of autoinflammatory diseases caused by mutations in genes associated with proteasome degradation or cytoplasmic RNA- and DNA-sensing pathways.

Objective: This study aimed to unveil the molecular pathogenesis of a patient with novel type I interferonopathy, for which no known genetic mutations have been identified.

Methods: We performed the whole-exome sequencing of a 1-month-old boy with novel type I interferonopathy. We also investigated proteasome activities using patient-derived B lymphoblastoid cell lines (LCLs) and normal LCLs transduced with the mutant gene.

Results: Whole-exome sequencing identified a de novo proteasome 20S subunit beta 9 (PSMB9) p.G156D mutation in the patient who developed fever, a chilblain-like skin rash, myositis, and severe pulmonary hypertension due to the hyperactivation of IFN-α. Patient-derived LCLs revealed reduced proteasome activities, and exogenous transduction of mutant PSMB9 p.G156D into normal LCLs significantly suppressed proteasome activities, and the endogenous PSMB9 protein was lost along with the reduction of other immunoproteasome subunits, PSMB8 and PSMB10 proteins. He responded to the administration of a Janus kinase inhibitor, tofacitinib, and he was successfully withdrawn from venoarterial extracorporeal membranous oxygenation. At age 7 months, he received an unrelated cord blood transplantation. At 2 years posttransplantation, he no longer required tofacitinib and experienced no disease recurrence.

Conclusions: We present the case of a patient with a novel type I interferonopathy caused by a de novo PSMB9 p.G156D mutation that suppressed the wild-type PSMB9 protein expression. Janus kinase inhibitor and stem cell transplantation could be curative therapies in patients with severe interferonopathies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jaci.2021.03.010DOI Listing
March 2021

Two Distinct Conformations in 34 FliF Subunits Generate Three Different Symmetries within the Flagellar MS-Ring.

mBio 2021 03 2;12(2). Epub 2021 Mar 2.

Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan

The bacterial flagellum is a protein nanomachine essential for bacterial motility. The flagellar basal body contains several ring structures. The MS-ring is embedded in the cytoplasmic membrane and is formed at the earliest stage of flagellar formation to serve as the base for flagellar assembly as well as a housing for the flagellar protein export gate complex. The MS-ring is formed by FliF, which has two transmembrane helices and a large periplasmic region. A recent electron cryomicroscopy (cryoEM) study of the MS-ring formed by overexpressed FliF revealed a symmetry mismatch between the S-ring and inner part of the M-ring. However, the actual symmetry relation in the native MS-ring and positions of missing domains remain obscure. Here, we show the structure of the M-ring by combining cryoEM and X-ray crystallography. The crystal structure of the N-terminal half of the periplasmic region of FliF showed that it consists of two domains (D1 and D2) resembling PrgK D1/PrgH D2 and PrgK D2/PrgH D3 of the injectisome. CryoEM analysis revealed that the inner part of the M-ring shows a gear wheel-like density with the inner ring of C23 symmetry surrounded by cogs with C11 symmetry, to which 34 copies of FliF fitted well. We propose that FliF adopts two distinct orientations in the M-ring relative to the rest of FliF, with 23 chains forming the wheel and 11 chains forming the cogs, and the 34 chains come together to form the S-ring with C34 symmetry for multiple functions of the MS-ring. The bacterial flagellum is a motility organelle formed by tens of thousands of protein molecules. At the earliest stage of flagellar assembly, a transmembrane protein, FliF, forms the MS-ring in the cytoplasmic membrane as the base for flagellar assembly. Here, we solved the crystal structure of a FliF fragment. Electron cryomicroscopy (cryoEM) structural analysis of the MS-ring showed that the M-ring and S-ring have different rotational symmetries. By docking the crystal structure of the FliF fragment into the cryoEM density map of the entire MS-ring, we built a model of the whole periplasmic region of FliF and proposed that FliF adopts two distinct conformations to generate three distinct C11, C23, and C34 symmetries within the MS-ring for its multiple functions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/mBio.03199-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8092281PMC
March 2021

Site-directed crosslinking identifies the stator-rotor interaction surfaces in a hybrid bacterial flagellar motor.

J Bacteriol 2021 Feb 22. Epub 2021 Feb 22.

Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.

The bacterial flagellum is the motility organelle powered by a rotary motor. The rotor and stator elements of the motor are located in the cytoplasmic membrane and cytoplasm. The stator units assemble around the rotor, and an ion flux (typically H or Na) conducted through a channel of the stator induces conformational changes that generate rotor torque. Electrostatic interactions between the stator protein PomA in (MotA in ) and the rotor protein FliG have been shown by genetic analyses, but have not been demonstrated biochemically. Here, we used site-directed photo- and disulfide-crosslinking to provide direct evidence for the interaction. We introduced a UV-reactive amino acid, -benzoyl-L-phenylalanine (BPA), into the cytoplasmic region of PomA or the C-terminal region of FliG in intact cells. After UV irradiation, BPA inserted at a number of positions in PomA formed a crosslink with FliG. PomA residue K89 gave the highest yield of crosslinks, suggesting that it is the PomA residue nearest to FliG. UV-induced crosslinking stopped motor rotation, and the isolated hook-basal body contained the crosslinked products. BPA inserted to replace residues R281 or D288 in FliG formed crosslinks with the stator protein, MotA. A cysteine residue introduced in place of PomA K89 formed disulfide crosslinks with cysteine inserted in place of FliG residues R281 and D288, and some other flanking positions. These results provide the first demonstration of direct physical interaction between specific residues in FliG and PomA/MotA.The bacterial flagellum is a unique organelle that functions as a rotary motor. The interaction between the stator and rotor is indispensable for stator assembly into the motor and the generation of motor torque. However, the interface of the stator-rotor interaction has only been defined by mutational analysis. Here, we detected the stator-rotor interaction using site-directed photo- and disulfide-crosslinking approaches. We identified several residues in the PomA stator, especially K89, that are in close proximity to the rotor. Moreover, we identified several pairs of stator and rotor residues that interact. This study directly demonstrates the nature of the stator-rotor interaction and suggests how stator units assemble around the rotor and generate torque in the bacterial flagellar motor.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JB.00016-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8092157PMC
February 2021

Role of the N- and C-terminal regions of FliF, the MS ring component in flagellar basal body.

J Bacteriol 2021 Feb 22. Epub 2021 Feb 22.

Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.

The MS ring is a part of the flagellar basal body and formed by 34 subunits of FliF, which consists of a large periplasmic region and two transmembrane segments connected to the N- and C-terminal regions facing the cytoplasm. A cytoplasmic protein, FlhF, which determines the position and number of the basal body, supports MS ring formation in the membrane in species. In this study, we constructed FliF deletion mutants that lack 30 or 50 residues from the N-terminus (ΔN30 and ΔN50), and 83 (ΔC83) or 110 residues (ΔC110) at the C-terminus. The N-terminal deletions were functional and conferred motility of cells, whereas the C-terminal deletions were nonfunctional. The mutants were expressed in to determine whether an MS ring could still be assembled. When co-expressing ΔN30FliF or ΔN50FliF with FlhF, fewer MS rings were observed than with the expression of wild-type FliF, in the MS ring fraction, suggesting that the N-terminus interacts with FlhF. MS ring formation is probably inefficient without FlhF. The deletion of the C-terminal cytoplasmic region did not affect the ability of FliF to form an MS ring because a similar number of MS rings were observed for ΔC83FliF as with wild-type FliF, although further deletion of the second transmembrane segment (ΔC110FliF) abolished it. These results suggest that the terminal regions of FliF have distinct roles; the N-terminal region for efficient MS ring formation and the C-terminal region for MS ring function. The second transmembrane segment is indispensable for MS ring assembly.The bacterial flagellum is a supramolecular architecture involved in cell motility. At the base of the flagella, a rotary motor that begins to construct an MS ring in the cytoplasmic membrane comprises 34 transmembrane proteins (FliF). Here, we investigated the roles of the N and C terminal regions of FliF, which are MS rings. Unexpectedly, the cytoplasmic regions of FliF are not indispensable for the formation of the MS ring, but the N-terminus appears to assist in ring formation through recruitment of FlhF, which is essential for flagellar formation. The C-terminus is essential for motor formation or function.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JB.00009-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8092156PMC
February 2021

Analysis of disease model iPSCs derived from patients with a novel Fanconi anemia-like IBMFS ADH5/ALDH2 deficiency.

Blood 2021 Apr;137(15):2021-2032

Laboratory of DNA Damage Signaling, Department of Late Effects Studies, Radiation Biology Center.

We have recently discovered Japanese children with a novel Fanconi anemia-like inherited bone marrow failure syndrome (IBMFS). This disorder is likely caused by the loss of a catabolic system directed toward endogenous formaldehyde due to biallelic variants in ADH5 combined with a heterozygous ALDH2*2 dominant-negative allele (rs671), which is associated with alcohol-induced Asian flushing. Phytohemagglutinin-stimulated lymphocytes from these patients displayed highly increased numbers of spontaneous sister chromatid exchanges (SCEs), reflecting homologous recombination repair of formaldehyde damage. Here, we report that, in contrast, patient-derived fibroblasts showed normal levels of SCEs, suggesting that different cell types or conditions generate various amounts of formaldehyde. To obtain insights about endogenous formaldehyde production and how defects in ADH5/ALDH2 affect human hematopoiesis, we constructed disease model cell lines, including induced pluripotent stem cells (iPSCs). We found that ADH5 is the primary defense against formaldehyde, and ALDH2 provides a backup. DNA repair capacity in the ADH5/ALDH2-deficient cell lines can be overwhelmed by exogenous low-dose formaldehyde, as indicated by higher levels of DNA damage than in FANCD2-deficient cells. Although ADH5/ALDH2-deficient cell lines were healthy and showed stable growth, disease model iPSCs displayed drastically defective cell expansion when stimulated into hematopoietic differentiation in vitro, displaying increased levels of DNA damage. The expansion defect was partially reversed by treatment with a new small molecule termed C1, which is an agonist of ALDH2, thus identifying a potential therapeutic strategy for the patients. We propose that hematopoiesis or lymphocyte blastogenesis may entail formaldehyde generation that necessitates elimination by ADH5/ALDH2 enzymes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/blood.2020009111DOI Listing
April 2021

[Flagellar related genes and functions in Vibrio].

Nihon Saikingaku Zasshi 2020 ;75(3):195-214

Division of Biological Science, Graduate School of Science, Nagoya University.

Bacteria can move or swim by flagella. On the other hand, the motile ability is not necessary to live at all. In laboratory, the flagella-deficient strains can grow just like the wild-type strains. The flagellum is assembled from more than 20 structural proteins and there are more than 50 genes including the structural genes to regulate or support the flagellar formation. The cost to construct the flagellum is so expensive. The fact that it evolved as a motor organ means even at such the large cost shows that the flagellum is essential for survival in natural condition. In this review, we would like to focus on the flagella-related researches conducted by the authors and the flagellar research on Vibrio spp.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3412/jsb.75.195DOI Listing
February 2021

Digenic mutations in and impair formaldehyde clearance and cause a multisystem disorder, AMeD syndrome.

Sci Adv 2020 Dec 18;6(51). Epub 2020 Dec 18.

Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan.

Rs671 in the aldehyde dehydrogenase 2 gene () is the cause of Asian alcohol flushing response after drinking. ALDH2 detoxifies endogenous aldehydes, which are the major source of DNA damage repaired by the Fanconi anemia pathway. Here, we show that the rs671 defective allele in combination with mutations in the alcohol dehydrogenase 5 gene, which encodes formaldehyde dehydrogenase ( ), causes a previously unidentified disorder, AMeD (aplastic anemia, mental retardation, and dwarfism) syndrome. Cellular studies revealed that a decrease in the formaldehyde tolerance underlies a loss of differentiation and proliferation capacity of hematopoietic stem cells. Moreover, double-deficient mice recapitulated key clinical features of AMeDS, showing short life span, dwarfism, and hematopoietic failure. Collectively, our results suggest that the combined deficiency of formaldehyde clearance mechanisms leads to the complex clinical features due to overload of formaldehyde-induced DNA damage, thereby saturation of DNA repair processes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/sciadv.abd7197DOI Listing
December 2020

Novel COL4A1 mutations identified in infants with congenital hemolytic anemia in association with brain malformations.

Hum Genome Var 2020 Nov 27;7(1):42. Epub 2020 Nov 27.

Department of Transfusion Medicine and Cell Processing, Tokyo Women's Medical University, Tokyo, Japan.

Genetic causes of undiagnosed hemolytic anemia in nineteen patients were analyzed by whole-exome sequencing, and novel COL4A1 variants were identified in four patients (21%). All patients were complicated with congenital malformations of the brain, such as porencephaly or schizencephaly. In these patients, hemolysis became less severe within 2 months after birth, and red cell transfusion was no longer required after 50 days, whereas chronic hemolysis continued.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41439-020-00130-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7695726PMC
November 2020

Two Aldehyde Clearance Systems Are Essential to Prevent Lethal Formaldehyde Accumulation in Mice and Humans.

Mol Cell 2020 12 3;80(6):996-1012.e9. Epub 2020 Nov 3.

Department of Innovative Medical Science, Tokai University School of Medicine, Isehara, Japan.

Reactive aldehydes arise as by-products of metabolism and are normally cleared by multiple families of enzymes. We find that mice lacking two aldehyde detoxifying enzymes, mitochondrial ALDH2 and cytoplasmic ADH5, have greatly shortened lifespans and develop leukemia. Hematopoiesis is disrupted profoundly, with a reduction of hematopoietic stem cells and common lymphoid progenitors causing a severely depleted acquired immune system. We show that formaldehyde is a common substrate of ALDH2 and ADH5 and establish methods to quantify elevated blood formaldehyde and formaldehyde-DNA adducts in tissues. Bone-marrow-derived progenitors actively engage DNA repair but also imprint a formaldehyde-driven mutation signature similar to aging-associated human cancer mutation signatures. Furthermore, we identify analogous genetic defects in children causing a previously uncharacterized inherited bone marrow failure and pre-leukemic syndrome. Endogenous formaldehyde clearance alone is therefore critical for hematopoiesis and in limiting mutagenesis in somatic tissues.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.molcel.2020.10.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7758861PMC
December 2020

Comprehensive pathogen detection in sera of Kawasaki disease patients by high-throughput sequencing: a retrospective exploratory study.

BMC Pediatr 2020 10 15;20(1):482. Epub 2020 Oct 15.

Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.

Background: Kawasaki disease (KD) is an idiopathic systemic vasculitis that predominantly damages coronary arteries in children. Various pathogens have been investigated as triggers for KD, but no definitive causative pathogen has been determined. As KD is diagnosed by symptoms, several days are needed for diagnosis. Therefore, at the time of diagnosis of KD, the pathogen of the trigger may already be diminished. The aim of this study was to explore comprehensive pathogens in the sera at the acute stage of KD using high-throughput sequencing (HTS).

Methods: Sera of 12 patients at an extremely early stage of KD and 12 controls were investigated. DNA and RNA sequences were read separately using HTS. Sequence data were imported into the home-brew meta-genomic analysis pipeline, PATHDET, to identify the pathogen sequences.

Results: No RNA virus reads were detected in any KD case except for that of equine infectious anemia, which is known as a contaminant of commercial reverse transcriptase. Concerning DNA viruses, human herpesvirus 6B (HHV-6B, two cases) and Anelloviridae (eight cases) were detected among KD cases as well as controls. Multiple bacterial reads were obtained from KD and controls. Bacteria of the genera Acinetobacter, Pseudomonas, Delfita, Roseomonas, and Rhodocyclaceae appeared to be more common in KD sera than in the controls.

Conclusion: No single pathogen was identified in serum samples of patients at the acute phase of KD. With multiple bacteria detected in the serum samples, it is difficult to exclude the possibility of contamination; however, it is possible that these bacteria might stimulate the immune system and induce KD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12887-020-02380-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7557310PMC
October 2020

MicroRNA-155-5p Plays a Critical Role in Transient Leukemia of Down Syndrome by Targeting Tumor Necrosis Factor Receptor Superfamily Members.

Cell Physiol Biochem 2020 Oct;54(5):994-1012

Department of Hematology, Iuliu Hatieganu University of Medicine and Pharmacy Cluj Napoca, Romania,

Background/aims: Down syndrome associated disorders are caused by a complex genetic context where trisomy 21 is a central component in relation to other changes involving epigenetic regulators and signaling molecules. This unique genetic context is responsible for the predisposition of people with Down syndrome to acute leukemia. Although, the research in this field has discovered some important pathogenic keys, the exact mechanism of this predisposition is not known.

Methods: In this study we applied functional enrichment analysis to evaluate the interactions between genes localized on chromosome 21, genes already identify as having a key role in acute leukemia of Down syndrome, miRNAs and signaling pathways implicated in cancer and cell development and found that miR-155 has a high impact in genes present on chromosome 21. Forward, we performed next generation sequencing on DNA samples from a cohort of patients diagnosed with acute leukemia of Down syndrome and in vitro functional assay using a CMK-86 cell line, transfected with either mimic or inhibitor of the microRNA-155-5p.

Results: Our results show that the epigenetic alteration of the TNF superfamily receptors in Down syndrome, which can be correlated to microRNA-155-5p aberrant activity, may play an important role in cell signaling and thus be linked to acute myeloid leukemia.

Conclusion: Some genes, already shown to be mutated in AML-DS, are potential targets for miR-155. Our results show that the epigenetic alteration of the TNF superfamily receptors in Down syndrome may play an important role in cell signaling and thus be linked to acute myeloid leukemia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.33594/000000283DOI Listing
October 2020

Reduced-intensity conditioning is effective for hematopoietic stem cell transplantation in young pediatric patients with Diamond-Blackfan anemia.

Bone Marrow Transplant 2021 May 18;56(5):1013-1020. Epub 2020 Sep 18.

Department of Pediatrics, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative therapy for the hematologic manifestations of Diamond-Blackfan anemia (DBA). However, data regarding the optimal conditioning regimen for DBA patients are limited. We retrospectively compared the outcomes of DBA patients who underwent HSCT using either myeloablative conditioning (MAC) or reduced-intensity conditioning (RIC) regimens. The patients belonged to a cohort treated at our hospitals between 2000 and 2018. HSCT was performed in 27 of 165 patients (16.4%). The median age at the time of HSCT was 3.6 years. Stem cell sources included bone marrow for 25 patients (HLA-matched sibling donors, n = 5; HLA-mismatched related donors, n = 2; HLA-matched/mismatched unrelated donors, n = 18) or cord blood for 2 patients. MAC or RIC regimens were used in 12 and 15 patients, respectively. Engraftment was successful in all 27 patients who underwent HSCT. Three patients who underwent HSCT using MAC regimens developed sinusoidal obstruction syndrome. The 3-year overall survival (OS) and failure-free survival rates (FFS) post-transplantations were 95.2% and 88.4%, respectively, with no significant differences between MAC and RIC regimens. Our data suggest that HSCTs using RIC regimens are effective and obtain engraftment with excellent OS and FFS for young DBA patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41409-020-01056-1DOI Listing
May 2021

Detection of boson peak and fractal dynamics of disordered systems using terahertz spectroscopy.

Phys Rev E 2020 Aug;102(2-1):022502

Division of Materials Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.

The boson peak is a largely unexplained excitation found universally in the terahertz vibrational spectra of disordered systems; the so-called fracton is a vibrational excitation associated with the self-similar structure of monomers in polymeric glasses. We demonstrate that such excitations can be detected using terahertz spectroscopy. In the case of fractal structures, we determine the infrared light-vibration coupling coefficient for the fracton region and show that information concerning the fractal and fracton dimensions appears in the exponent of the absorption coefficient. Finally, using terahertz time-domain spectroscopy and low-frequency Raman scattering, we experimentally observe these universal excitations in a protein (lysozyme) system that has an intrinsically disordered and fractal structure and argue that the system should be considered a single supramolecule. These findings are applicable to amorphous and fractal objects in general and will be valuable for understanding universal dynamics of disordered systems via terahertz light.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevE.102.022502DOI Listing
August 2020

The flagellar motor of undergoes major structural remodeling during rotational switching.

Elife 2020 09 7;9. Epub 2020 Sep 7.

Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, United States.

The bacterial flagellar motor switches rotational direction between counterclockwise (CCW) and clockwise (CW) to direct the migration of the cell. The cytoplasmic ring (C-ring) of the motor, which is composed of FliG, FliM, and FliN, is known for controlling the rotational sense of the flagellum. However, the mechanism underlying rotational switching remains elusive. Here, we deployed cryo-electron tomography to visualize the C-ring in two rotational biased mutants in . We determined the C-ring molecular architectures, providing novel insights into the mechanism of rotational switching. We report that the C-ring maintained 34-fold symmetry in both rotational senses, and the protein composition remained constant. The two structures show FliG conformational changes elicit a large conformational rearrangement of the rotor complex that coincides with rotational switching of the flagellum. FliM and FliN form a stable spiral-shaped base of the C-ring, likely stabilizing the C-ring during the conformational remodeling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7554/eLife.61446DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7505661PMC
September 2020

Risk factors for secondary poor graft function after bone marrow transplantation in children with acquired aplastic anemia.

Pediatr Transplant 2020 11 2;24(7):e13828. Epub 2020 Sep 2.

Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.

In patients with acquired AA, PGF is a major cause of cytopenia after hematopoietic stem cell transplantation. An increased incidence of PGF, especially sPGF, has been noted after the introduction of the FLU/CY regimen in children with acquired AA. To clarify the risk factors for sPGF, the clinical data of 49 patients (median age, 11 years; range, 1-19 years) with AA who received allogeneic BMT at Nagoya University Hospital from 1997 to 2016 were analyzed. Out of the 49 patients, 7 developed sPGF, and the 5-year CI was 0.15 (95% CI, 0.04-0.25). Five received the FLU/CY regimen, and the 5-year CI of sPGF was significantly higher in patients who received the regimen (0.36; 95% CI, 0.12-0.62) than in those who were conditioned with the non-FLU/CY regimen (0.06; 95% CI, 0.01-0.17; P = .01). The multivariate analysis confirmed that the FLU/CY regimen (hazard ratio, 6.12; 95% CI, 1.16-32.4; P = .03) was a significant risk factor for sPGF. sPGF improved spontaneously without stem cell boost infusions in 5 patients, ranging from 460 to 3539 days after BMT. The 10-year CI of the spontaneous trilineage recovery was 0.83 (95% CI, 0.00-0.97), and all 7 patients are alive. The FLU/CY regimen was identified as a risk factor for the sPGF development in patients with AA. The establishment of the optimal conditioning regimens for children with AA is warranted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/petr.13828DOI Listing
November 2020

Current insights into the treatments of severe aplastic anemia in China.

Int J Hematol 2020 Sep 3;112(3):292-299. Epub 2020 Aug 3.

Department of Pediatrics, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.

Recently, several studies have been conducted to generate considerable evidence regarding unique treatments for severe aplastic anemia (SAA) in China. Haploidentical donor hematopoietic stem cell transplantation (HID-HSCT) showed an overall survival rate (80.3-86.1%) comparable to those with immunosuppressive therapy (IST) and matched related donor (MRD)- and matched unrelated donor (MUD)-HSCT. Failure-free survival of HID-HSCT was also comparable (76.4-85.0%) to those of MRD- and MUD-HSCT and better than IST in patients < 40 years. Although these results are promising, HID-HSCT should be regarded as a salvage therapy when young patients fail to respond to IST. Porcine anti-human lymphocyte immunoglobulin (pALG) showed similar or superior overall response at 6 months compared to rabbit anti-human thymocyte immunoglobulin (rATG) (64.0-79.4% in the pALG-group vs.48.1-64.7% in the rATG-group) as a first-line IST. Promising hematological response (28.4-33.3%) was observed in patients with refractory AA following infusion of the mesenchymal stromal cells (MSCs) derived from the bone marrow of allogeneic donors. pALG can replace rATG as an immunosuppressive drug and MSCs infusion can be used as a second-line treatment for refractory SAA. We believe that this review contributes to refine the global practices for SAA treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12185-020-02955-1DOI Listing
September 2020

Successful treatment with i.v. immunoglobulin and rituximab for bronchiolitis obliterans associated with paraneoplastic pemphigus.

J Dermatol 2020 Oct 12;47(10):e368-e370. Epub 2020 Jul 12.

Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1346-8138.15496DOI Listing
October 2020

Myelodysplastic syndromes in a pediatric patient with Cri du Chat syndrome with a ring chromosome 5.

Int J Hematol 2020 Nov 9;112(5):728-733. Epub 2020 Jun 9.

Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan.

Few hematological complications have previously been reported in association with Cri du Chat syndrome (CdCS). A case of myelodysplastic syndromes (MDS) in a pediatric patient with CdCS is herein presented. A 17-year-old female with CdCS caused by ring chromosome 5 was admitted to the hospital for investigation of a 1-month history of anemia. Based on the morphological findings of bone marrow, the patient was diagnosed with refractory cytopenia with multilineage dysplasia. The risk group was classified as intermediate-1 in the International Prognostic Scoring System (IPSS), and low in the revised IPSS. Assessment by microarray comparative genomic hybridization (CGH) identified the breakpoints of ring chromosome 5 as 46,XX,r(5)(p14.3q35.3). This revealed that the 5q terminal deletion did not include the common deleted region of MDS with del(5q). Treatment with azacitidine was initiated to control disease progression and improve quality of life. At baseline, the patient had a mean transfusion requirement of 3 units/month, which decreased to 2 units/month after six cycles of azacitidine and to 1 unit/month after 10 cycles of azacitidine. Cytopenia observed in the presented case seemed irrelevant to ring chromosome 5 which is the causative cytogenetic abnormality of CdCS, and further analyses may be needed to clarify the pathogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12185-020-02909-7DOI Listing
November 2020

Assembly mechanism of a supramolecular MS-ring complex to initiate bacterial flagellar biogenesis in species.

J Bacteriol 2020 Jun 1. Epub 2020 Jun 1.

Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan

The bacterial flagellum is an organelle responsible for motility and has a rotary motor comprising the rotor and the stator. Flagellar biogenesis is initiated by the assembly of the MS-ring, a supramolecular complex embedded in the cytoplasmic membrane. The MS-ring consists of a few dozen copies of the transmembrane FliF protein, and is an essential core structure which is a part of the rotor. The number and location of the flagella are controlled by the FlhF and FlhG proteins in some species. However, there is no clarity on the factors initiating MS-ring assembly, and contribution of FlhF/FlhG to this process. Here, we show that FlhF and a C-ring component FliG facilitate MS-ring formation. When FliF alone was expressed in cells, MS-ring formation rarely occurred, indicating the requirement of other factors for MS-ring assembly. Consequently, we investigated if FlhF aided FliF in MS-ring assembly. We found that FlhF allowed GFP-fused FliF to localize at the cell pole in a cell, suggesting that it increases local concentration of FliF at the pole. When FliF was co-expressed with FlhF in cells, the MS-ring was effectively formed, indicating that FlhF somehow contributes to MS-ring formation. The isolated MS-ring structure was similar to the MS-ring formed by FliF. Interestingly, FliG facilitates MS-ring formation, suggesting that FliF and FliG assist in each other's assembly into the MS-ring and C-ring. This study aids in understanding the mechanism behind MS-ring assembly using appropriate spatial/temporal regulations. Flagellar formation is initiated by the assembly of the FliF protein into the MS-ring complex, embedded in the cytoplasmic membrane. The appropriate spatial/temporal control of MS-ring formation is important for the morphogenesis of the bacterial flagellum. Here, we focus on the assembly mechanism of FliF into the MS-ring. FlhF, a positive regulator of the number and location of flagella, recruits the FliF molecules at the cell pole and facilitates MS-ring formation. FliG also facilitates MS-ring formation. Our study showed that these factors control flagellar biogenesis in by initiating the MS-ring assembly. Furthermore, it also implies that flagellar biogenesis is a sophisticated system linked with the expression of certain genes, protein localization and a supramolecular complex assembly.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JB.00236-20DOI Listing
June 2020

Functional characterization of multiple PAS domain-containing diguanylate cyclases in sp. PCC 6803.

Microbiology (Reading) 2020 07;166(7):659-668

Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama 6-6-07, Sendai 980-8579, Japan.

Bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a second messenger known to control a variety of bacterial processes. The model cyanobacterium, sp. PCC 6803, has a score of genes encoding putative enzymes for c-di-GMP synthesis and degradation. However, most of them have not been functionally characterized. Here, we chose four genes in (), which encode proteins with a GGDEF, diguanylate cyclase (DGC) catalytic domain and multiple Per-ARNT-Sim (PAS) conserved regulatory motifs, for detailed analysis. Purified DgcA, DgcB and DgcC were able to catalyze synthesis of c-di-GMP from two GTPs . DgcA had the highest activity, compared with DgcB and DgcC. DgcD did not show detectable activity. DgcA activity was specific for GTP and stimulated by the divalent cations, magnesium or manganese. Full activity of DgcA required the presence of the multiple PAS domains, probably because of their role in protein dimerization or stability. mutants carrying single deletions of were not affected in their growth rate or biofilm production during salt stress, suggesting that there was functional redundancy . In contrast, overexpression of resulted in increased biofilm formation in the absence of salt stress. In this study, we characterize the enzymatic and physiological function of DgcA-DgcD, and propose that the PAS domains in DgcA function in maintaining the enzyme in its active form.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1099/mic.0.000929DOI Listing
July 2020